JP2011171024A - Led lighting device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an LED lighting device preventing flicker of light-emitting diodes caused by a stray capacitance between the diodes and a case, irrespective of a structure of a power supply device. <P>SOLUTION: The LED lighting device is provided with a grounded metallic case 2 with an opening 12, an LED module 3 arranged inside the case 2 so as irradiation light of the light-emitting diodes 20 to be irradiated outside from the opening 12 of the case 2 and having regions formed with stray capacitances generated at a substrate 21 to be relatively large and small in an arrangement relation with the case 2, an insulator 4 arranged between the case 2 and the other face of the substrate 21 at a side of the region with relatively large stray capacitance with the case 2, and a power supply device for lighting the light-emitting diodes 20 of the LED module 3. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

The present invention relates to an LED illumination device that uses a light emitting diode as a light source and uses the emitted light for illumination.

In this type of LED lighting device, a plurality of light emitting diodes are mounted on a substrate to form an LED module, and are disposed in, for example, a metal housing (apparatus body). Since the LED module is connected to an output line from a power supply device that turns on the light emitting diode, some LED lighting devices have a casing grounded by a ground wire.

It is known that a stray capacitance is generated between the light emitting diode and the housing, and a pulse current due to a noise voltage superimposed on the output line of the power supply device flows from the light emitting diode to the ground line through the stray capacitance. As a result, it is known that flickering or destruction occurs in the light emitting diode. There has been proposed an LED lighting device that prevents destruction of a light emitting diode (LED) due to the noise voltage (see, for example, Patent Document 1). This LED lighting device of the prior art is composed of an LED unit and a power supply unit, and the power supply unit houses a rectifier circuit and a DC-DC converter circuit in a metal case.

Then, a ground noise voltage bypass capacitor for connecting the secondary side ground of the DC-DC converter circuit to the metal case is provided, and an earth wire for connecting the metal case and the conductive portion of the LED unit is provided. The electric capacity is set larger than the combined stray capacity between each LED of the LED unit and the conductive portion. As a result, when a ground noise voltage is applied to the AC power source, even if a pulse current due to the ground noise voltage flows through the stray capacitance of the LED unit, the pulse current is bypassed through the capacitor. It is possible to prevent a pulse current exceeding the withstand voltage of the LED from flowing, and the LED is not destroyed.

However, the LED lighting device of the above prior art prevents a pulse current exceeding the withstand voltage of the LED from flowing, and the pulse current due to the ground noise voltage and the high-frequency current leaked from the DC-DC converter circuit have a large stray capacitance. It may flow to ground through between the LED and the conductive part, and thereby the lighting state of each LED may flicker. In order to prevent the flickering of the LED, it is necessary to considerably increase the capacitor capacity of the LED lighting device. As a result, the capacitor is increased in size and cost, and the LED lighting device is increased in size and cost. Furthermore, since the capacitor is connected between the secondary side ground of the DC-DC converter circuit and the metal case, it becomes an expensive part requiring a withstand voltage of at least several hundred volts. This further increases the cost of the LED lighting device.

JP 2008-130438 A (page 4-6, FIG. 1)

In the LED lighting device of Patent Document 1, flickering of the light emitting diode due to stray capacitance between the light emitting diode and the LED unit cannot be sufficiently suppressed. Although it is conceivable to use a noise filter circuit to prevent flickering of the light emitting diode due to the ground noise voltage, the addition of the noise filter circuit increases the size and cost of the LED lighting device.

An object of the present invention is to provide an LED lighting device that prevents flickering of a light emitting diode caused by stray capacitance between the light emitting diode and a housing, regardless of the configuration of the power supply device.

The invention of the LED lighting device according to claim 1 includes a metal housing having an opening and being grounded; a substrate on which the light emitting diode is mounted on one surface side, and the emitted light of the light emitting diode Is disposed in the housing so as to be emitted outward from the opening of the housing, and a region is formed in which the stray capacitance generated in the substrate is relatively large in the positional relationship with the housing. An LED module; an insulator disposed between the housing and the other surface of the substrate on the region side where the stray capacitance with the housing is relatively large; a power supply device that lights a light emitting diode of the LED module; It is characterized by comprising.

In the present invention and the following inventions, each configuration is as follows unless otherwise specified.

The LED module and the power supply device are electrically connected by an output line (lead wire) of the power supply device. Noise is generated between the output line and a grounded case (earth).

“Relatively small stray capacitance” means that the stray capacitance is so small that even if noise is applied between the small stray capacitance substrate area and the housing, flickering of the light-emitting diode is difficult for humans to see. It means that. On the other hand, “relatively large stray capacitance” means stray capacitance in which flickering of light-emitting diodes that can be seen by humans occurs when noise is applied between the substrate region and the housing having a large stray capacitance. It means that.

The magnitude of the stray capacitance can be formed by various methods such as the type, thickness and size of the substrate, the type of wiring pattern formed on the substrate, the width and thickness, and the arrangement of the light emitting diodes.

The insulator may be any material that insulates the substrate and the housing of the LED module, such as an insulating plate or an insulator made of a resin such as silicone resin. The thickness may be set as appropriate according to the size of the stray capacitance.

According to the present invention, since the insulator is interposed between the other surface of the substrate on the region side where the stray capacitance with the housing is relatively large and the housing, the stray capacitance with the housing is relatively reduced. The stray capacitance between the large substrate region side and the housing is reduced. As a result, the stray capacitance between each area of the board and the housing is small, and even if noise is generated between the output line of the power supply device and the housing (earth), the current flowing through the light-emitting diode leaks to the ground side. Becomes extremely small and flickering of the light emitting diode is prevented.

The invention of the LED illumination device according to claim 2 is the invention of the LED illumination device according to claim 1, wherein the substrate has a plurality of light emitting diodes connected in series by a wiring pattern formed on one surface side thereof. It is connected in series and parallel, and at least one of the width and thickness of the wiring pattern on the region side where the stray capacitance with the housing is relatively large is formed to be larger than the other region side. And

By connecting a plurality of light emitting diodes in series or in series and parallel, the formation of the wiring pattern is simplified and the width and thickness of the wiring pattern can be easily changed.

According to the present invention, the region of the substrate in which the stray capacitance with the casing is relatively large is easily formed by changing at least one of the width and thickness of the wiring pattern.

According to the first aspect of the present invention, the substrate region in which the stray capacitance with the housing is relatively large is formed, the other surface of the substrate on the region side where the stray capacitance with the housing is relatively large, and the housing Since an insulator is disposed between the power supply device and the power supply device, noise can be reduced while reducing the cost of the insulator compared to the entire substrate and the housing. Thus, since it is not configured to be highly functional, it is possible to reduce the size and reduce the cost, and as a result, it is possible to provide a LED lighting device that is reduced in size and cost.

According to the invention of claim 2, in the substrate of the LED module, at least one of the width and the thickness of the wiring pattern on the region side where the stray capacitance with the housing is relatively large is larger than the other region side. Since it is formed, it is possible to relatively easily form a substrate region in which the stray capacitance with the housing is relatively large, and thereby the cost of the LED lighting device can be further reduced.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a partially cutaway schematic side view of an LED lighting device showing Embodiment 1 of the present invention. Similarly, the schematic perspective view of a LED lighting apparatus. Similarly, the schematic side view of an LED lighting device. Similarly, an LED module is shown, (a) is a schematic top view, and (b) is a schematic side view.

Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

In the present invention, the LED module is formed with a region where the stray capacitance with the housing is relatively large on the substrate, and the insulator is the other side of the substrate on the region side where the stray capacitance with the housing is relatively large. It is arrange | positioned between a surface and a housing | casing. By the arrangement of the insulator, the stray capacitance between the substrate region side and the housing having a relatively large stray capacitance with the housing is reduced, and the stray capacitance between each region of the substrate and the housing is reduced. . As a result, even if noise is applied between the substrate and the grounded casing (earth), the current flowing through the light emitting diode is extremely less likely to leak to the ground side, and flickering of the light emitting diode is prevented. . Since the power supply device does not need to be configured to suppress the generation of noise, the LED lighting device can be reduced in size and cost. In addition, since the insulator is partially disposed between the housing and the substrate region side where the stray capacitance with the housing is relatively large, it is not disposed between the entire substrate and the housing. The amount of the insulator used can be reduced, and the LED lighting device can be reduced at a low cost.

1 to 4 show a first embodiment of the present invention, FIG. 1 is a partially cutaway schematic side view of an LED lighting device, FIG. 2 is a schematic perspective view of the LED lighting device, and FIG. 3 is a schematic of the LED lighting device. FIG. 4 shows an LED module, (a) is a schematic top view, and (b) is a schematic side view.

In FIG. 1 and FIG. 3, the LED lighting device 1 includes a housing 2, an LED module 3, an insulator 4, and a power supply device 5. The LED lighting device 1 is a downlight embedded in a ceiling surface or the like.

In FIG. 1, the housing 2 is formed having an instrument body 6 and a decorative frame 7. The instrument body 6 is molded by aluminum die casting, has a storage space 8 for storing the LED module 3 and the like inside, and is formed in a substantially cylindrical shape having various heat radiation fins 9 on the outer surface side. The decorative frame 7 is made of ABS resin, and is formed in a substantially bowl shape having various reinforcing pieces 10 and a circular flange portion 11 on the outer surface side. The decorative frame 7 is screwed with a screw (not shown) from the upper surface between the radiating fins 9, 9 of the instrument body 6 and is integrated with the instrument body 6.

And the inner surface 7a of the decorative frame 7 is formed in the reflective surface, for example by white coating, and becomes the opening part 12 of the housing | casing 2 which radiate | emits the radiated light from the LED module 3. FIG. The innermost side of the opening 12 is formed in an annular step 13. The step portion 13 is provided with a translucent cover 14 without being fixed. The translucent cover 14 is made of, for example, acrylic resin and is formed in a disk shape. A pair of attachment springs 15, 15 are attached to the outer surface of the decorative frame 7 to fix the housing 2 to the ceiling or the like by sandwiching the ceiling surface or the like with the flange portion 11.

As shown in FIG. 2, the casing 2 has a top plate 16 attached to the upper end side of the instrument body 6, and a terminal block 17 is disposed on the top plate 16. As shown in FIG. 3, a connector 19 attached to the distal end side of the power cord 18 led out from the power supply device 5 is detachably attached to the terminal block 17. Then, when the connector 18 is attached to the terminal block 17, a ground wire (not shown) of the power cord 18 is electrically connected to the instrument body 6 made of aluminum die cast. That is, the housing 2 is at the ground potential via the power supply device 5.

As shown in FIG. 1, the LED module 3 is disposed in a storage space 8 of the instrument body 6. The LED module 3 includes a plurality of light emitting diodes 20 and a substrate 21 so that the light emitting diodes 20 face the opening 12 side of the decorative frame 7, and the emitted light of the light emitting diodes 20 is opened. 12 is disposed in the housing 2 so as to be emitted outward.

The light emitting diode 20 is a surface mount type and is formed so as to emit visible light, for example, white light. The substrate 21 is made of, for example, an aluminum (Al) plate having a thickness of 1 mm. As shown in FIG. 4, a plurality of light emitting diodes 20 are concentrically arranged on one surface 21a side through an insulating layer (not shown). Is implemented. That is, four light emitting diodes 20 are mounted around the center 21 c of the substrate 21, eight on the outer side, and 14 on the outer side so as to be substantially equidistantly spaced on a concentric circle.

A connector portion 22 is disposed on the outer peripheral end side of the one surface 21 a of the substrate 21. A lead wire 23 wired to the other surface 21 b side of the substrate 21 and connected to the terminal block 17 is attached to the connector portion 22.

A plurality of wiring patterns 24 made of copper foil are formed on one surface 21a of the substrate 21 via an insulating layer (not shown). The wiring pattern 24 is different in width and pattern shape, and a plurality of light emitting diodes 20 are connected in series and connected to the connector portion 22. Then, the distance between the wiring patterns 24 and 24 in the region on the left side in FIG. 4A from the center 21c of the substrate 21 is formed to be larger than the distance between the wiring patterns 24 and 24 in the right region. Yes. That is, on one surface 21a of the substrate 21, the total area (copper foil area) of the wiring pattern 24 in the right region in FIG. 4A is equal to the total area of the wiring pattern 24 in the left region in FIG. It is formed so as to be larger than (copper foil area).

Also, the thickness of the wiring pattern 24 in the right region in FIG. 4A is formed to 50 μm, for example, and is larger than the thickness of the wiring pattern 24 in the left region in FIG. . As described above, when the LED module 3 is housed and disposed in the housing space 8 of the housing 2 alone, a large stray capacitance is present between the housing 2 and the region on the right side of the substrate 21 in FIG. A small stray capacitance is generated between the region on the left side of the substrate 21 in FIG. That is, the LED module 3 is forcibly formed with a region in which the stray capacitance generated on the substrate 21 is relatively large in the arrangement relationship with the housing 2. Here, the small stray capacitance is set such that when a predetermined DC voltage is applied to the light emitting diodes 20 connected in series, a current leaked to the ground side through the stray capacitance becomes extremely small.

Note that the substrate 21 has an insulating layer (not shown) formed on the surface of the wiring pattern 24 excluding the light emitting diode 20 and the connector portion 22 and on the portion where the wiring pattern 24 is not formed.

Further, the wiring pattern 24 may have a width, a pattern shape, a thickness, and the like so that a plurality of light emitting diodes 20 are connected in series and parallel. Even in this case, a region where the stray capacitance generated in the substrate 21 is relatively large in the arrangement relationship with the housing 2 is formed.

A hole 25 is formed in the center 21 c of the substrate 21. A screw (not shown) is inserted into the hole 25, and the screw is screwed into a screw hole (not shown) of the housing 2 via a spacer 26 as shown in FIG. Thereby, the LED module 3 is temporarily fixed to the housing 2 in the storage space 8 of the housing 2. The spacer 26 is formed in a cylindrical shape having a hollow through which a screw passes, and the substrate 21 is separated from the housing 2 by the entire length thereof.

In addition, the substrate 21 has four holes 27 formed at equal intervals on a concentric circle at a predetermined distance from the center 21c, as shown in FIG. In the hole 27, a screw that penetrates the instrument main body 6 from the upper surface of the instrument main body 6 of the housing 2 is inserted through a spacer 28 as shown in FIG. The spacer 28 is formed to have a diameter larger than that of the spacer 26, but its entire length is formed to be equal to the spacer 26.

In FIG. 1, the screw inserted through the hole 27 of the substrate 21 is screwed into the reflector unit 29. Thus, the LED module 3 is sandwiched between the spacer 26 and the spacer 28 and the reflector unit 29 and is fixed to the instrument body 6 in the storage space 8 of the housing 2.

The reflector unit 29 is made of, for example, PC / ASA, and a reflector 30 that individually surrounds the light emitting diodes 20 is formed. The reflector 30 is formed in a substantially rectangular object, and controls the light distribution by the emitted light of the light emitting diode 20. The size of the reflector 30 is set so as to be close to the translucent cover 14 when the appliance body 6 and the decorative frame 7 of the housing 2 are integrated.

The insulator 4 is made of, for example, a silicone resin, and is disposed between the other surface 21b of the substrate 21 and the housing 2 as shown in FIG. And in the board | substrate 21, it arrange | positions between the area | region side with a large floating capacitance with the housing | casing 2, and the housing | casing 2. FIG. That is, a silicone resin as the insulator 4 is embedded between the housing 21 and the other surface 21b of the right region of the substrate 21 in FIG. A space is formed between the other surface 21b of the left region of the substrate 21 in FIG.

As shown in FIG. 3, the power supply device 5 is accommodated in a power supply unit 31. A power cord 18 having an output line and a ground line of the power supply device 5 is led out from the power supply unit 31 and is detachably connected to the terminal block 17 of the housing 2 by a connector 19.

The power supply device 5 is formed of a known circuit that lights the light emitting diode 20 of the LED module 3. The power supply device 5 and the power supply unit 31 are grounded by a ground wire (not shown), and the metal instrument body 6 of the housing 2 is grounded.

Next, the operation of the first embodiment of the present invention will be described.

The light emitting diode 20 generates heat when turned on. In order to quickly transmit and dissipate this heat, the substrate 21 of the LED module 3 is a metal plate having good thermal conductivity, such as an aluminum (Al) plate. Even if the substrate 21 is a resin, a metal film is formed on the surface to improve heat transfer. The housing 2 is made of a metal such as aluminum (Al) by improving heat dissipation to the external space.

Thus, if the board | substrate 21 and the housing | casing 2 are each formed with a metal, a stray capacitance will inevitably generate | occur | produce between them. This stray capacitance is large enough to cause the current flowing through the light emitting diode 20 to leak to the ground side. In order to reduce the stray capacitance between the substrate 21 and the housing 2, one method is to reduce the area of the metal film (copper foil) forming the wiring pattern 24. The generated heat is difficult to transfer quickly through the metal film, and the light emitting diode 20 may rise in temperature and have a short life.

As another method for reducing the stray capacitance between the substrate 21 and the housing 2, the insulator 4 is disposed between the substrate 21 and the housing 2. For example, a silicone resin as the insulator 4 is embedded and interposed between the substrate 21 and the housing 2. However, since the silicone resin is interposed at least across the entire area between the substrate 21 and the housing 2, the amount of the silicone resin used is large, which is an element of high cost of the LED lighting device.

However, in the LED lighting device 1 of the present invention, the metal fixture body 6 of the housing 2 has a substrate 21 having a large stray capacitance with the housing 2 (region on the right side in FIG. 4A). A silicone resin, which is an insulator 4, is disposed between the other surface 21 b and the instrument body 6. By providing the insulator 4, the stray capacitance between the region of the substrate 21 having a large stray capacitance with the housing 2 and the instrument body 6 is reduced. The substrate 21 has a small stray capacitance with the instrument body 6 over the entire area.

Even if predetermined power is supplied from the power supply device 6 and noise is generated between the output body 23 connected to the terminal block 17 of the housing 2 and the instrument body 6, the instrument body 6 and the substrate 21 It is extremely small that the current flowing through the light emitting diode 20 leaks to the ground side through the stray capacitance. As a result, flickering of the light emitting diode 20 is prevented.

Then, the light from the light emitting diode 20 generated in the region on the right side in FIG. 4A due to the lighting of the light emitting diode 20 is transferred to the substrate 21 through the wiring pattern 24 and an insulating layer (not shown). Further, heat from the light emitting diode 20 generated in the left region in FIG. 4A is transferred to the substrate 21 through the wiring pattern 24 and an insulating layer (not shown), and further, on the right side in FIG. 4A. Heat is transferred to the wiring pattern 24 in the region and transferred to the substrate 21.

The heat transferred to the substrate 21 is transferred from the substrate 21 to the insulator 4, transferred from the insulator 4 to the housing 2 (the instrument body 6), and released from the housing 2 to the external space. In this way, the temperature rise of the light emitting diode 20 mounted in the right region in FIG. 4A of the substrate 21 is suppressed, and the temperature rise of the light emitting diode 20 mounted in the left region in FIG. It is suppressed. That is, the area on the left side of the substrate 21 in FIG. 4A represents the total area of the wiring pattern 24 that can suppress the temperature rise of the light emitting diode 20 mounted in the area and reduce the stray capacitance with the housing 2. As shown, the wiring pattern (copper foil) 24 is formed.

As described above, the region of the substrate 21 where the stray capacitance with the housing 2 is relatively large is formed, and the other surface 21b of the substrate 21 on the region side where the stray capacitance with the housing 2 is large and the housing By disposing the insulator 4 between the two, the insulator 4 can be reduced as compared with the case where the insulator 4 is disposed between the entire substrate 21 and the housing 2, and cost can be reduced. In addition, since the power supply device 5 is not configured to have a high function so as to prevent the generation of noise, the power supply device 5 can be reduced in size and cost, thereby reducing the size of the LED lighting device 1 and reducing the cost. can do.

The region of the substrate 21 where the stray capacitance with the housing 2 is relatively large can be easily formed depending on the size, such as the width and thickness, of the wiring pattern 24. The cost can be reduced.

INDUSTRIAL APPLICABILITY The present invention can be used for a lighting fixture attached to a light bulb type lamp such as an LED bulb or a construction such as a ceiling.

DESCRIPTION OF SYMBOLS 1 ... LED lighting apparatus, 2 ... Housing | casing, 3 ... LED module, 4 ... Insulator, 5 ... Power supply device, 12 ... Opening part, 20 ... Light emitting diode, 21 ... Board | substrate

Claims (2)

A metal housing that has an opening and is grounded; and a substrate on which the light emitting diode is mounted on one surface side, and the emitted light of the light emitting diode is emitted outward from the opening of the housing An LED module that is disposed in the housing and has a region in which the stray capacitance generated in the substrate is relatively large in the arrangement relationship with the housing; and the stray capacitance with the housing is relative And an insulator disposed between the other surface of the substrate on the large area side and the housing; and a power supply device for lighting the light emitting diode of the LED module. . The substrate has a plurality of light emitting diodes connected in series or in series and parallel with a wiring pattern formed on one side of the substrate, and a wiring pattern on a region side where the stray capacitance with the housing is relatively large. 2. The LED lighting device according to claim 1, wherein at least one of the width and the thickness is formed so as to be larger than the other region side.

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